Economic interdependence of several distinct mutually-trading off-Earth settlement communities is the only plausible path to viability of any of them.
The opening of Mars, its moons, Deimos and Phobos, along with access to near Earth and Main Belt asteroids, is vital to the long-term survival prospects of any pioneer industrial and exporting settlement on the Moon.
To this end, MMM sees the following developments as part of "the critical path"
Mars Permafrost Explorer -- The opportunity to pre-test such a probe in Earth orbit to improve our knowledge of terrestrial tundra resources, makes this an easy sell.
Ground Truth Permafrost Tappers -- Orbital surveys will not be much good unless calibrated by well-scattered on-site drill cores. Further, only by actual on-site taps can we tell either the percentage of water content or its freshness or salinity or how we can best tap the deposit.
Mars Lavatube Explorer -- The opportunity to pre-test such a probe in Earth orbit to improve our knowledge of lava flow terrain, makes this a logical priority. The results could be far less important for geology than for future Mars settlement scenario options. Ancient near-surface Martian limestone caves could also be identified.
Mars topographic map with accurate elevations from which basin and watershed divides can be traced along with their overflow dam points. From this potential primitive and immature drainage patterns can be sketched. This will help avoid siting an outpost in a future flood plain.
Geochemical orbital mapper -- A refly of the instruments aboard Lunar Prospector.
Geochemical ground truth probes -- We lack even rudimentary mineralogical analysis of typical Martian soils. Without this, the path of industrial development on Mars remains totally fog-bound.
North & South Polar weather station net
Antarctic Mars Training Camp Base in one of the cold but "Dry Valleys" like Wright or Taylor. This should be a permanent establishment at which survival gear and methods developed for the Mars frontier can be tested, and prospective expedition members trained.
"Redhouse" Wild Flora Experimentation Projects. See the article with this name on page 5.
Adoption of the Zodiac-based Mars Calendar of Dr. Robert Zubrin as published in Ad Astra Nov/Dec, 93, pp. 25-7 "A Calendar for Mars", with the friendly modifications detailed in MMM #73, Mar '94, pp. 6-7. Official support should be sought from:
NSS, and The Planetary Society
NASA, ESA, Russian, Japanese Space agencies
IAU (International Astronomical Union)
SFWA (Science Fiction Writers of America)